Technical Field
The invention relates to a method of manufacturing of glassine paper.
Background Art
Glassine release base paper is a special paper grade which strongly distinguish from common bulk grades such as newsprint paper, supercalendered uncoated magazine paper (SC-paper) and coated magazine paper printing paper (LWC, MFC).
Typically the glassine paper is produced so that the base paper including the surface closing with film-forming products is manufactured in a paper machine and is reeled up as machine rolls. Commonly the base paper is dried and then remoisturized to the level needed for super calendaring. The moisture content in the base paper is typically is very high, about 15-20% of the solid contents of the paper. Due to the drying and re-moisturizing the paper cross directional moisture content profile becomes substantially even. The machine rolls are stored at least 2 hours, in order to even out of the moisture left in the paper. After the moisture has stabilized the base paper is treated in an off-line supercalender in order to provide desired properties of the glassine paper.
As an example of such an off-line supercalender solution it is referred to document JP2009-155758A.
The standard manufacturing process has several drawbacks. For example, it requires a process involving two separate steps; the paper machine and the super calender. In some cases it may be required that there are even two separate super calenders per one paper machine in order that the super calendering process can follow the machine production as the calendering speed is lower than the paper machine speed. This increases space requirement and also investment costs. Additionally, the intermediate stage for evening out the moisture in the paper consumes time, requires additional human resources and makes the process more complex. In view of the above prior art, it is the object of the invention to provide an improved method of manufacturing of glassine paper with properties meeting at least the values described above, which improved the efficiency of the prior art manufacturing process.